While it is a key aspect of structural analyses that support current Performance-Based Seismic Engineering (PBSE), 'structural collapse' is not clearly defined or directly simulated in the PBSE methodology. 'Collapse' is now either assessed indirectly based on lateral displacement ('drift') analysis results that exceed engineering judgment-based predefined limits, or is implied when the numerical analysis solution algorithm being used fails to converge. The ability to accurately simulate structural collapse is critical for implementing PBSE.
Accurate determination of collapse will enable designers to identify prudent levels of displacement demand that remain away from the collapse limit state. Objective - This project supports improved Performance-Based Seismic Engineering (PBSE) via evaluating the capabilities of commercial structural analysis software to simulate structural sidesway collapse accurately. This project:. Identifies and assesses critical issues concerning nonlinear mechanics of structures at collapse or near-collapse, to improve analytical accuracy and consistency;.
Simulation results agree well with experimental results. Finally, the software is applied to analyse a real building destroyed by the Wenchuan earthquake and. The WTC Collapse Simulator is an interactive application which models the collapse of. The Exterior Walls - A square tube forming the outside of the building.
Verifies the accuracy of practitioner-oriented structural analysis software packages for simulating sidesway collapse; and,. Develops guidelines on the levels of sophistication necessary to accurately simulate large displacement (near-collapse) response. What is the new technical idea? NIST GCR 09-917-2 (NIST 2009) identified improving analytical models and demand assessment for buildings near collapse from seismic loading as the second highest priority research area in support of full implementation of Performance-Based Seismic Engineering (PBSE). NIST GCR 13-917-23 (NIST 2013) identified improving analytical models and simulation capabilities for buildings in near-collapse seismic loading as a high priority research topic.
Commonly used practitioner-oriented collapse assessment analysis tools do not directly simulate collapse but instead require monitoring of other demands (e.g., drift) that are indirectly associated with collapse, such as the analytical results reported in FEMA P695 (FEMA 2009). In spite of this imprecision, the ASCE/SEI 7 Standard (ASCE 2010) uses the probability of structural collapse as the key parameter to define seismic risk and corresponding minimum design loads. This project posits the new technical idea of assessing collapse behavior based on combining basic nonlinear structural collapse mechanics theory with sophisticated research-oriented nonlinear finite element modeling and simulation. Comparisons of these collapse mechanisms with maximum drifts computed using (less sophisticated) practitioner-oriented software packages will be performed to verify current collapse prediction capabilities in those packages. The knowledge gained will then be applied to develop a rational, rigorous, and comprehensive methodology to measure structural performance based on the corresponding limits of acceptance criteria currently used in the ASCE/SEI 41 standard (ASCE 2013) that were developed in FEMA 273 (FEMA 1997) over 18 years ago and are currently being investigated by a NIST extramurally funded project.
Once this methodology is developed, practitioners will be able to perform detailed ASCE/SEI 41 nonlinear dynamic sidesway assessment on both global and local structural responses using practitioner-oriented software packages with confidence. What is the research plan? The first phase of this project involves theoretical investigation of basic structural collapse mechanics to identify the fundamental issues that must be included in an analytical model to capture sidesway collapse behavior. Key elements of this work are identifying the means to simulate the behavior analytically and verifying the numerical algorithms and associated accuracies obtained from current practitioner-oriented software packages. Simple structural moment frames and frame components are used in the study, keying on sidesway mechanism formation.
Extreme Loading Software – Applied Science International Australia Extreme Loading Software from Applied Science International (ASI) is a unique simulation technology for three dimensionally modelling and analysing the demolition of structures subjected to extreme loads: terrorist attack, bomb blasts, earthquakes, cyclonic force winds and other unplanned disasters. Liberty Industrial trading as ASI Australia is the Australian agent for Extreme Loading for Structures Software from Applied Science International (US). The software enables us to model specific demolition scenarios long before site work commences and serves as a key risk minimisation strategy for clients with large, technically challenging projects. By modelling a structure and then running the demolition plan, we can test several different plans and 'what-if' scenarios. The software allows us to visually demonstrate to the client what will happen in any given scenario.
The vulnerability simulations that the system generates provide views of assessments that are easily understood by engineer and non-engineer alike. This gives owners and decision makers a clearer perspective on what they need to know to protect their people, their property and their future. Live Simulation Extreme Loading for Structures Software can model a building collapse with realistic visualisation of resulting damage and debris. It can be applied to almost any structure from large processing plants to high rise buildings, historical structures, bridges and stadiums. A near-virtual reality scenario allows the viewer to see a full motion video of what will happen whether it’s demolition pre-weakening, a bomb within a building’s perimeter, an earthquake beneath it or a cyclone assaulting it from the side.